Data from the FDR and reports from the crew show a normal approach and normal handling of the aircraft until it descended to about 150 feet agl and was approaching over the end of the runway. At that point the first officer's attention was diverted to controlling the aircraft as it encountered some turbulence and possibly a wind shift close to the ground. He allowed the aircraft to drift to the right of the runway centre line, and it appears that he may have started to flare the aircraft early, stopping the descent at about 30 feet agl. The captain at this point, with the engine power at idle and the aircraft close to the ground, felt they were committed to a landing but was concerned that the aircraft had stopped descending and was right of centre line. Because fog was reducing his visibility along the runway, he was not able to determine how far the aircraft had travelled down the runway and, therefore, wanted to get the aircraft on the runway as quickly as possible. He took over control of the aircraft and applied hard left rudder input to bring the aircraft back to the runway centre line. The left rudder input caused the aircraft to roll left sufficiently for the left wing to contact the runway surface on touch down. The pilot-flying transitioned to visual flight when the aircraft was at decision height, 200 feet agl, and approaching the high intensity runway approach lights. The captain estimated the forward visibility to be about 4 000 feet at that time. Once the aircraft passed beyond the approach lights, it is likely that forward visibility was more restricted, but it could not be determined to what extent. The first weather observations reported a visibility of one quarter mile and remained at that throughout the morning with one observation reporting one eighth of a mile. In conditions of reduced visibility, it is desirable to have the aircraft set for landing and only be required to flare to land before passing beyond the high intensity approach lights. In this instance, several control inputs were required to position the aircraft, and a transfer of control between the flight crew members took place after the aircraft passed beyond the approach lights, likely in reduced forward visibility.Analysis Data from the FDR and reports from the crew show a normal approach and normal handling of the aircraft until it descended to about 150 feet agl and was approaching over the end of the runway. At that point the first officer's attention was diverted to controlling the aircraft as it encountered some turbulence and possibly a wind shift close to the ground. He allowed the aircraft to drift to the right of the runway centre line, and it appears that he may have started to flare the aircraft early, stopping the descent at about 30 feet agl. The captain at this point, with the engine power at idle and the aircraft close to the ground, felt they were committed to a landing but was concerned that the aircraft had stopped descending and was right of centre line. Because fog was reducing his visibility along the runway, he was not able to determine how far the aircraft had travelled down the runway and, therefore, wanted to get the aircraft on the runway as quickly as possible. He took over control of the aircraft and applied hard left rudder input to bring the aircraft back to the runway centre line. The left rudder input caused the aircraft to roll left sufficiently for the left wing to contact the runway surface on touch down. The pilot-flying transitioned to visual flight when the aircraft was at decision height, 200 feet agl, and approaching the high intensity runway approach lights. The captain estimated the forward visibility to be about 4 000 feet at that time. Once the aircraft passed beyond the approach lights, it is likely that forward visibility was more restricted, but it could not be determined to what extent. The first weather observations reported a visibility of one quarter mile and remained at that throughout the morning with one observation reporting one eighth of a mile. In conditions of reduced visibility, it is desirable to have the aircraft set for landing and only be required to flare to land before passing beyond the high intensity approach lights. In this instance, several control inputs were required to position the aircraft, and a transfer of control between the flight crew members took place after the aircraft passed beyond the approach lights, likely in reduced forward visibility. The flight crew was certified and qualified for the flight in accordance with existing regulations. The aircraft weight and centre of gravity were within limits. There was no evidence of malfunction or component failure of the aircraft that would contribute to the cause of the accident. The first officer was at the controls during the approach. Visibility along the runway was reduced by fog. The aircraft drifted above the glide slope and right of the runway centre line as it passed over the runway threshold. The captain took control of the aircraft and applied hard left rudder at 30 feet agl. The aircraft rolled left and landed firmly on the runway with 11.5 degrees of left bank. The aircraft left wing contacted the runway surface on touch down. The aircraft cockpit voice recorder was not functioning during the occurrence flight.Findings The flight crew was certified and qualified for the flight in accordance with existing regulations. The aircraft weight and centre of gravity were within limits. There was no evidence of malfunction or component failure of the aircraft that would contribute to the cause of the accident. The first officer was at the controls during the approach. Visibility along the runway was reduced by fog. The aircraft drifted above the glide slope and right of the runway centre line as it passed over the runway threshold. The captain took control of the aircraft and applied hard left rudder at 30 feet agl. The aircraft rolled left and landed firmly on the runway with 11.5 degrees of left bank. The aircraft left wing contacted the runway surface on touch down. The aircraft cockpit voice recorder was not functioning during the occurrence flight. The aircraft rolled left and the left wing struck the runway surface on touch down after the pilot applied hard left rudder control in the landing flare to align the aircraft with the runway centre line. The captain's late take-over of control and the reduced visibility along the runway were likely contributing factors to the occurrence.Causes and Contributing Factors The aircraft rolled left and the left wing struck the runway surface on touch down after the pilot applied hard left rudder control in the landing flare to align the aircraft with the runway centre line. The captain's late take-over of control and the reduced visibility along the runway were likely contributing factors to the occurrence.